Cracked Block Options

My Model A also has a crack in this area. It is not as large as yours, but it is in the exact same place. In most cases this is caused by freezing. In my experiences, it is not uncommon to find cracks in this area. Another area that is well known for cracking is directly under the water pump.

I would not consider brazing or welding to be an option for making a repair with a crack like this. I say this because the cast iron in this area is usually quite thin. Applying heat to thin cast iron may result in larger problems than you have now.

I have used JB Weld to repair the crack in my Model A block. I used a small Dremel tool to clean the area around the crack. I drilled several very small holes on both sides of the crack. These holes were used to press the JB Weld into, so the epoxy would have something to anchor to. I also drilled a small hole at each end of the crack to prevent spreading.

Before applying the JB Weld I cleaned the area with acetone. I used the “slow” curing JB Weld rather than the quick setting type. I applied two thin coats. After the epoxy partially set up to a tacky stage I pressed a piece of 80 grit sandpaper into the tacky epoxy to give it the look and texture of cast iron. After the epoxy completely dried, I applied a coat of paint to the area using a small brush.

This repair has lasted several years without a failure. I hope your luck is as good as mine.
 
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In 1998 our club did the repair tent at the Reno meet. A guy came in with much the same crack you show but it was so bad the pieces had fallen out. I believe it was three pieces. When I first saw it the side of the engine looked as though it were breathing. Perceptible movement in and out, So I was alarmed and told him we had sold all the engines we had on hand. He assured me he didn't want anything but to change his oil and then be on his way to Alaska the following morning, with Bill Lancaster and a couple of others. The block was held together with JB Weld and he made it up and back though he didn't follow Lancaster to the last 1000 miles to get above the Arctic Circle. Bill assured me the car had performed admirably the whole trip to Alaska and back.
 
Thanks everyone for the advice and tips. I'll give JB weld my best shot then see how it goes. That's a cool story about the A going to Alaska with a "breathing" block. Thanks again everyone.
 
Another Question, what tool gave you the best results grinding on the block? dremel, angle grinder, 1/4" die grinder. I imagine the die grinder would have the best control/power.

Is there a stone or bur style bit that worked well for you?

Thanks Again
 
Forget the crack. If I understand you correctly, oil is not draining out of the pan correctly/slowly. Pull the pan , manifolds and valve cover plug the main and cam oil tubes and clean all the sludge. You can drop the pan upside down on cement, and the dipper tray will come out. There’s a good chance your oil pump screen is severely plugged as well. You might want to check bearing clearences as well. Now you know what shape your engine is, and its clean, go ahead on the crack. Otherwise if sludged up, you’ll have a short drive.
New engines are $4000 or so.its worth the precautions!
 
Cleaning oil pans is a good idea if you don't know the condition very well.

Just drill the ends of the cracks, JB weld and lock&stich it when it gets rebuilt.
 
Chuck Sea/Tac said:
Forget the crack. If I understand you correctly, oil is not draining out of the pan correctly/slowly. Pull the pan, manifolds and valve cover plug the main and cam oil tubes and clean all the sludge. You can drop the pan upside down on cement, and the dipper tray will come out. There’s a good chance your oil pump screen is severely plugged as well. You might want to check bearing clearences as well. Now you know what shape your engine is, and its clean, go ahead on the crack. Otherwise if sludged up, you’ll have a short drive.
New engines are $4000 or so.its worth the precautions!
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No, what he said was he let the car sit for three days before draining the oil (so any water would settle to the bottom of the pan). Then he put a cup under the drain plug to catch what drained when he removed the drain plug (to check for water).
 
I would suggest that you get some Marine Tex, sort of J.B. Weld on steroids. Back in ,my commercial fishing days I had a friend who had an engine crack , in his boat, in order to get in he sealed it up with Marine Tex. Made it back---4-5 years later it was still going strong.
 
Steve_KS said:
I'm a total novice I've had an A all of 4 days now so I'm looking for some advice.


I looked this car over 4 years ago, I don’t remember the crack then but perhaps the paint was hiding it. The car was driven very little in the last 4 years and always had antifreeze so I highly doubt freezing caused the crack recently. I just acquired the car and hauled it home so it’s my problem now. I let it sit 3 days and collected the first cup of oil during an oil change. I don’t see any coolant in the oil but it smells like gas, I suppose that’s normalish?

As I understand it I have 5 options now and lots of questions.

  • Have the block welded. I’ve read this requires all machined surfaces being redone and then the motor rebuilt. Probably costs more than a new motor or block.
  • Get a new motor of some kind. This one supposedly has upgrades like; balanced crank, insert bearings, oil filter, high compression head. Replacement cost will probably exceed the cars value.
  • Braze the crack. I have a feeling the block was possibly brazed in the past and the crack has reemerged. I need to grind off the paint to confirm that though.
  • Lock-N-Stitch the block. This looks real neat, does anyone know if it can be done on curved surfaces or only flat? My crack seems to go down through a curve. Can this be done in the car? Then flush the coolant after or add a screen before the water pump.
  • Grind and fill with JB weld. Has anyone had success on such a long crack?
  • Keep driving it as is. Do these cracks generally grow until they are fatal or stay about the same size?
I am tempted to just drive it until something fatal happens then find a new motor? If the damage is already done and a new motor is in my future why not drive it into the ground first. Maybe this is a bad idea for some reason unknown to me. Which is why I’m asking your experts.

Thanks for any input.
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I like the JB weld solution from fordwife, as a method that hurts nothing and may well solve the crack leak! Here is my added reasoning, My model A is not a pressurized cooling system, and if yours is like mine, with no pressure build in the block, then if the JB weld solution is done well on clean metal, there is no coolant pressure that is going to force it out. And in tun with how I operate, sometimes cheep works just fine. If not, then start moving up the cost chain to fix.
 
Like others, the JB weld will work, but first drain, drill ends, remove paint/ Drexel tool grind area, degrease with alcohol or brake cleaner. I patched holes in ‘58 Harley heads and it stayed good for over a decade.

+ on dropping oil pan. I just did mine. PO said he religiously maintained after engine rebuild, but there was 3/8 sludge in pan. Yes, take the cover off the pump to clean the screen and assembly.

Best of luck.
 
Another endorsement for the JB Weld. I repaired a Ford 8n tractor block 20 years ago and its still good.
I've also had good luck with Bar's leak tablets.

Randall
 
Thanks all for the help, I drilled the ends, used a dremmel to grind out the crack a tad, cleaned with wire wheel in a die grinder, then lacquer thinner. Finnaly filling with JB weld.

Using a single sided razer as a putty knife/scraper worked great to apply the JB weld.

I tried the shop vac trick and connected it on the water inlet but it kept sucking the JB weld clean through the holes so they wouldn't stay plugged.

I've driven it ~ 20 miles since the patch and no leak yet so I'm keeping my fingers crossed and moved on to the next problem.

Thanks Again.
 
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